deduplicate installation instructions

doc/manual/src/installation/installing-binary.md

@@ -1,89 +1,111 @@
 # Installing a Binary Distribution
 
-The easiest way to install Nix is to run the following command:
+To install the latest version Nix, run the following command:
 
 ```console
 $ curl -L https://nixos.org/nix/install | sh
 ```
 
-This will run the installer interactively (causing it to explain what
-it is doing more explicitly), and perform the default "type" of install
-for your platform:
-- single-user on Linux
-- multi-user on macOS
+This performs the default type of installation for your platform:
 
-  > **Notes on read-only filesystem root in macOS 10.15 Catalina +**
-  >
-  > - It took some time to support this cleanly. You may see posts,
-  >   examples, and tutorials using obsolete workarounds.
-  > - Supporting it cleanly made macOS installs too complex to qualify
-  >   as single-user, so this type is no longer supported on macOS.
+- [Multi-user](#multi-user-installation):
+  - Linux with systemd and without SELinux
+  - macOS
+- [Single-user](#single-user-installation):
+  - Linux without systemd
+  - Linux with SELinux
 
-We recommend the multi-user install if it supports your platform and
-you can authenticate with `sudo`.
+We recommend the multi-user installation if it supports your platform and you can authenticate with `sudo`.
 
-# Single User Installation
-
-To explicitly select a single-user installation on your system:
+The installer can configured with various command line arguments and environment variables.
+To show available command line flags:
 
 ```console
-$ curl -L https://nixos.org/nix/install | sh -s -- --no-daemon
+$ curl -L https://nixos.org/nix/install | sh -s -- --help
 ```
 
-This will perform a single-user installation of Nix, meaning that `/nix`
-is owned by the invoking user. You can run this under your usual user
-account or root. The script will invoke `sudo` to create `/nix`
-if it doesn’t already exist. If you don’t have `sudo`, you should
-manually create `/nix` first as root, e.g.:
+To check what it does and how it can be customised further, [download and edit the second-stage installation script](#installing-from-a-binary-tarball).
+
+# Installing a pinned Nix version from a URL
+
+Version-specific installation URLs for all Nix versions since 1.11.16 can be found at [releases.nixos.org](https://releases.nixos.org/?prefix=nix/).
+The directory for each version contains the corresponding SHA-256 hash.
+
+All installation scripts are invoked the same way:
 
 ```console
-$ mkdir /nix
-$ chown alice /nix
+$ export VERSION=2.19.2 
+$ curl -L https://releases.nixos.org/nix/nix-$VERSION/install | sh
 ```
 
-The install script will modify the first writable file from amongst
-`.bash_profile`, `.bash_login` and `.profile` to source
-`~/.nix-profile/etc/profile.d/nix.sh`. You can set the
-`NIX_INSTALLER_NO_MODIFY_PROFILE` environment variable before executing
-the install script to disable this behaviour.
-
 # Multi User Installation
 
-The multi-user Nix installation creates system users, and a system
-service for the Nix daemon.
+The multi-user Nix installation creates system users and a system service for the Nix daemon.
+
+Supported systems:
 
-**Supported Systems**
 - Linux running systemd, with SELinux disabled
 - macOS
 
-You can instruct the installer to perform a multi-user installation on
-your system:
+To explicitly instruct the installer to perform a multi-user installation on your system:
 
 ```console
 $ curl -L https://nixos.org/nix/install | sh -s -- --daemon
 ```
 
-The multi-user installation of Nix will create build users between the
-user IDs 30001 and 30032, and a group with the group ID 30000. You
-can run this under your usual user account or root. The script
-will invoke `sudo` as needed.
+You can run this under your usual user account or `root`.
+The script will invoke `sudo` as needed.
+
+# Single User Installation
+
+To explicitly select a single-user installation on your system:
+
+```console
+$ curl -L https://nixos.org/nix/install | sh -s -- --no-daemon
+```
+
+In a single-user installation, `/nix` is owned by the invoking user.
+The script will invoke `sudo` to create `/nix` if it doesn’t already exist.
+If you don’t have `sudo`, manually create `/nix` as `root`:
+
+```console
+$ su root
+# mkdir /nix
+# chown alice /nix
+```
+
+# Installing from a binary tarball
+
+You can also download a binary tarball that contains Nix and all its dependencies:
+- Choose a [version](https://releases.nixos.org/?prefix=nix/) and [system type](../contributing/hacking.md#platforms)
+- Download and unpack the tarball
+- Run the installer
 
-> **Note**
+> **Example**
 >
-> If you need Nix to use a different group ID or user ID set, you will
-> have to download the tarball manually and [edit the install
-> script](#installing-from-a-binary-tarball).
+> ```console
+> $ pushd $(mktemp -d)
+> $ export VERSION=2.19.2
+> $ export SYSTEM=x86_64-linux
+> $ curl -LO https://releases.nixos.org/nix/nix-$VERSION/nix-$VERSION-$SYSTEM.tar.xz
+> $ tar xfj nix-$VERSION-$SYSTEM.tar.xz
+> $ cd nix-$VERSION-$SYSTEM
+> $ ./install
+> $ popd
+> ```
 
-The installer will modify `/etc/bashrc`, and `/etc/zshrc` if they exist.
-The installer will first back up these files with a `.backup-before-nix`
-extension. The installer will also create `/etc/profile.d/nix.sh`.
+The installer can be customised with the environment variables declared in the file named `install-multi-user`.
+
+## Native packages for Linux distributions
+
+The Nix community maintains installers for some Linux distributions in their native packaging format(https://nix-community.github.io/nix-installers/).
 
 # macOS Installation
 
+<!-- anchors to catch existing links -->
 []{#sect-macos-installation-change-store-prefix}[]{#sect-macos-installation-encrypted-volume}[]{#sect-macos-installation-symlink}[]{#sect-macos-installation-recommended-notes}
-<!-- Note: anchors above to catch permalinks to old explanations -->
 
-We believe we have ironed out how to cleanly support the read-only root
+We believe we have ironed out how to cleanly support the read-only root file system
 on modern macOS. New installs will do this automatically.
 
 This section previously detailed the situation, options, and trade-offs,
@@ -126,33 +148,3 @@ this to run the installer, but it may help if you run into trouble:
   boot process to avoid problems loading or restoring any programs that
   need access to your Nix store
 
-# Installing a pinned Nix version from a URL
-
-Version-specific installation URLs for all Nix versions
-since 1.11.16 can be found at [releases.nixos.org](https://releases.nixos.org/?prefix=nix/).
-The corresponding SHA-256 hash can be found in the directory for the given version.
-
-These install scripts can be used the same as usual:
-
-```console
-$ curl -L https://releases.nixos.org/nix/nix-<version>/install | sh
-```
-
-# Installing from a binary tarball
-
-You can also download a binary tarball that contains Nix and all its
-dependencies. (This is what the install script at
-<https://nixos.org/nix/install> does automatically.) You should unpack
-it somewhere (e.g. in `/tmp`), and then run the script named `install`
-inside the binary tarball:
-
-```console
-$ cd /tmp
-$ tar xfj nix-1.8-x86_64-darwin.tar.bz2
-$ cd nix-1.8-x86_64-darwin
-$ ./install
-```
-
-If you need to edit the multi-user installation script to use different
-group ID or a different user ID range, modify the variables set in the
-file named `install-multi-user`.

doc/manual/src/quick-start.md

@@ -11,7 +11,6 @@ to subsequent chapters.
    ```
 
    The install script will use `sudo`, so make sure you have sufficient rights.
-   On Linux, `--daemon` can be omitted for a single-user install.
 
    For other installation methods, see [here](installation/index.md).